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RLIUP Session5 Summary

RLIUP Session5 Summary. Massimiliano Ferro- L uzzi and Oliver Brüning. Session Goal:. Session Goal : Review the HL-LHC upgrade plans related to the ion physics program and summarize the required machine upgrades.

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RLIUP Session5 Summary

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  1. RLIUP Session5 Summary Massimiliano Ferro-Luzzi and Oliver Brüning

  2. Session Goal: Session Goal: • Review the HL-LHC upgrade plans related to the ion physics program and summarize the required machine upgrades. • Analyze the options for extended ion runs during the connection of LINAC4 to the PSB. • Review the schedule and operation options for the ion beam operation during the HL-LHC period. Session Content: • Experiment perspective. • Performance of the injectors with ions after LS1. • [Options for running the LHC with ions during the LINAC4 connection]. • How to run ions in the future? • Future heavy-ion performance of the LHC. 29-31. October; Review of the LHC and Injector Upgrade Plans; Archamps

  3. Run 2: ALICE Physics: Goals and Requests [Emilio Meschi] RLIUP 2013 - HI Plans - Experiments Perspective

  4. Experiments:[Emilio Meschi] • Physics highlights: • Quark-Gluon plasma and phase transition and the search for the critical point. • Physics requirements - wishes: • Need for control experiments (p-p data taking and p-Pb runs and runs at intermediate beam energies [e.g. Pb-Pb @ 5Tev, 5.5 TeV, p-Pb @ 5 TeV and 8.2 TeV]).  all asymmetric collision configurations imply configuration change between Beam1 and Beam2!  requires different machine configurations as compared to p-p operation • p-p runs require 5 order of magnitude lower luminosity in ALICE as for the GP experiments  Operational challenge? • Background considerations require a vacuum of 5 10-9 or better. 29-31. October; Review of the LHC and Injector Upgrade Plans; Archamps

  5. Experiments Perspective: • Performance wishes: • 3nbarn-1 by LS3 in ATLAS. All experiments like to collect at least 1nbarn-1 during RunII. • 10nbarn-1 for ALICE after upgrade during LS2. • LHCb: p-Pb NOT at the end of ion program of RunII compatibility with ALICE plan? • ALICE requires leveling during Pb-Pb and p-Pb (while ATLAS and CMS do not)  Physics and Machine coordination!!! • The Pb-Pb runs in 2015 and 2016 can NOT be grouped (trigger configurations)  No to an extended ion run as part of LS1.5 and the LINAC4 connection! • LHCb would like 10 times more integrated luminosity with p-Pb as compared to Run1. • ALICE polarity reversals on regular basis. • Performance wishes after LS2: • Different beam species: Pb-Pb, p-Pb, Ar-Ar, p-Ar • 10 fold increase in beam performance expected from ALICE  collimation upgrade and vacuum conditions? • LHCfinterested in running with Nitrogen and Oxygen?  Physics case @ LHCC required! 29-31. October; Review of the LHC and Injector Upgrade Plans; Archamps

  6. Performance of the injectors with ions after LS1: [Django] • Performance summary of RunI: • 2 bunches with 200ns spacing in the PS  24 bunches in the SPS  360 bunches in the LHC @ collision • Upgrade Plans: • Increasing the bunch intensity is not a viable option (IBS and luminosity burn off) • 100ns batch compression in the SPS (already envisaged for RunII in the PS but without the SPS injection upgrade  432 bunches for RunII). • Increasing the number of injections would increase the injection time and thus the emittance growth  keep the number of PS injections into the SPS at 12  requires SPS injection system upgrade (recuperated equipment from PSB energy upgrade, not requiring new kicker magnets)  624 bunches in the LHC @ collision • Requires higher bunch intensities in LEIR (already above design and currently limited)  further studies required • Slip stacking in the SPS to be re-evaluated  smaller bunch spacing (e.g. 50ns?) • LINAC3 pulsing @ 10Hz (source already pulsing @ 10Hz) 29-31. October; Review of the LHC and Injector Upgrade Plans; Archamps

  7. How to run ions in the future? [DetlefKuchler] • Performance summary of RunI: • Records: • 215 eµA Pb27+ out of the spectrometer • 31 eµA Pb54+ at the end of the linac • Operational: • 100-120 eµA Pb29+ out of the RFQ • 20-25 eµA Pb54+ at the end of the linac (TRA25) (≈ 50% of the design value) • Changing ion species takes time (4 weeks Pb-> Ar & 10 weeks Ar -> Pb) • Upgrade Plans: • 10Hz operation of the LINAC3 (source already running @10Hz) • Multi-charge acceleration. • New Oven design and test-stand (ca. 5MCHF)! • Wishes and requirements: • Dedicated ion run in 2015 for Machine Development and tests 29-31. October; Review of the LHC and Injector Upgrade Plans; Archamps

  8. Future heavy-ion performance of the LHC: [John Jowett] • RunII performance projections: • Bunch-by-bunch luminosity model required (IBS and SPS injection)! • 2.8 1027 cm-2 s-1 for ATLAS and CMS for Pb-Pb @ 6.5 Z TeV with 2011 scheme • 3.7 1027 cm-2 s-1 for ATLAS and CMS for Pb-Pb @ 6.5 Z TeV with 100ns BC. • Changing the magnetic configuration wrt the standard p-p run will take 1 to 2 days. • Before ALICE upgrade luminosity needs to be leveled at 1 1027 cm-2 s-1 (ATLAS and CMS are not limited in peak luminosity). • Luminosity decay dominated by burn-off • p-Pb: 2.5 - 7 1029cm-2 s-1 @ 4 Z TeV/c and 4.3 - 12 1029 cm-2 s-1 @ 7 Z TeV/c  BPM resolution! • RunIII projections: • 6 1027 cm-2 s-1 for Pb-Pb @ 6.5 Z TeV with 100ns batch compression and SPS injection system upgrade (6 x design). • Peak luminosity limitations: • Bound Free Pair Production and Electro Magnetic Disintegration and resulting secondary beams  DS collimators • IBS!!! possibility of Stochastic Cooling a la RHIC, 200MHz and 800MHz RF in LHC? 29-31. October; Review of the LHC and Injector Upgrade Plans; Archamps

  9. Summary and Questions: LS1.5 (9month shutdown between LS1 and LS2) is not desired by experiments. ALICE needs a clear commitment to a ‘standard running scenario’ but exceptional modifications for a given year are possible. Promising upgrade options for the machine should be further pursued (e.g. Stochastic cooling, 200MHz and 800MHz RF). Operation with different ion species needs to be requested well in advance! LHCC recommendation? DS collimators for IR1 and IR5 not yet foreseen! Injector: one could connect LINAC4 (50MeV protons) in 12 weeks but at reduced performance and without gain for LS2  LINAC2 backup and BCMS still to be analyzed LS2 duration with LINAC4 connection (as H- injector) will take 20.5 month (LINAC4 proper will take 9 month) 29-31. October; Review of the LHC and Injector Upgrade Plans; Archamps

  10. Reserve Transparencies 29-31. October; Review of the LHC and Injector Upgrade Plans; Archamps

  11. Heavy Ion Physics • QGP: what is it • A theoretical model of the phase of matter where partons are not (completely) confined • Produced in High-energy nucleus-nucleus interactions • Large energy density (~15 GeV/fm3 at LHC) over a large volume(~ 5000 fm3 at LHC) • Very high equivalent temperature (T~300 MeV) • Strongly interacting • How it is studied • Jets: energy loss mechanism - collective effects in QCD, medium density • Heavy flavour:mass dependence of energy loss - probe the medium transport properties • Quarkonium: quarkoniumdissociation and regeneration - probes deconfinementand medium temperature • Low-mass di-leptons: thermal radiation γ (àe+e-) - to map temperature and evolution • Proton-Ion: collective effects • pp physics probes quarks and gluons as “free particles” • Nuclear physics studies the bound states • HI physics studies the intermediate phases of QCD matter which prevailed shortly after the big-bang RLIUP 2013 - HI Plans - Experiments Perspective

  12. Run 2: ALICE RLIUP 2013 - HI Plans - Experiments Perspective • For 2015 pp need 5 orders of magnitude luminosity reduction in IP2 • no filling scheme tricks available at 25ns ~all bunches collide in ALICE (except effect of abort gap) • Larger β* not an option due to aperture issues in IP2 • Aseparation of order 5σ seems to be needed • Would the level of background in IP2 be lower than signal? Will depend on quality of vacuum • ALICE studied the beam-gas background conditions in LSS2-L assuming a 5 10-9 vacuum. • the result is a rather strong MB trigger contamination (~50%) at L=1 1029.  on the other hand the contamination at L=1 1030is ~10%, but a pileup of 10 in the TPC is the price to pay. • Further studies of optimization will be performed based on these results

  13. Upgrades and studies • Linac 3: increase intensity • 10Hz pulsing (included in consolidation - PIC) • multiple charge acceleration (unsure of benefit for LEIR) • LEIR: Intensity limitation • ~+40% needed for additional splitting, but cause presently unknown • PS: 50ns splitting or batch compression near transition • Tests of 2-bunch batch compression to 50ns with Ar • New cavity (Finemet) • Transition-distortion optics; imperfections? • SPS • PFL on MKP + MSI-V septum for 100ns rise time injection / batch spacing • New beam control allowing RF gymnastics for slip-stacking • Are resulting imperfections after slip stacking acceptable by the LHC? • Improvement of beam behaviour on flat bottom (RF noise…)

  14. Pb-Pb Summary: Peak luminosity & intensity(w.r.t. nominal) according to different schemes Slip stacking Peak luminosity 50ns batch compression in the PS Proposed Baseline (100ns) 2015 2011/2013 Nominal Batch spacing in the SPS (ns) Intensity/LHC ring Batch spacing in the SPS (ns)

  15. Schedule with LS1.5 • Ar2014-2015 … first Pb-Pb run in November 2015 same as baseline • Xecommissioning (Linac3/LEIR/PS/SPS) start early 2016 + FT Run in September 2016 • Switch to PbNovember 2016, recommissionPb ion chain • Stop protons 3 weeks before Xmas break • Pb source standby during Xmas (cf Xmas 2012) • Restart Pb ion chain in January • 3.5 (max) months Pb run: • Ion MDs in chain • Primary Pb in NA • 8+ week LHC Pb-Pb run (grouping of 2016 & 2017 “November” runs) • Restart with protons, next Pb ion run as p-Pb just before LS2 (2019?) (B.Mikulec, J.B.Lallement)

  16. Design Baseline and Performance Achieved “p-Pb not part of baseline” Pb-Pb p-Pb

  17. Reminder: Pb-p luminosity production in 2013 Intermediate filling scheme to limit the losses The LHC experiments asked us to change operating conditions every few days. Operating experience in all previous colliders has taught us that gradual optimisation of constant operating conditions is the path to high luminosity. Max. peak luminosity 1.15x1029cm-2.s-1! Increase of BLM monitor factor (losses at the start of the ramp), rematch injection energy to the SPS Increase of BLM monitor factor (losses end of ramp + squeeze) Increase bandwidth of orbit feedback IP1,5 separated VdM scans reduction of longitudinal blow-up at injection Increase of BLM monitor factor (losses during the squeeze), Nevertheless we fulfilled all requests, thanks to the quality of the LHC, meticulous planning andsome judicious risk-taking (with performance). So we do not need to fear “complicated” physics requests. 1x1029cm-2.s-1 Common frequency trimmed by -10Hz 27/01 07/02 RF frequencies

  18. p-Pb luminosity estimates for 2017 Performance for p-Pb in Run 2 • Increasing the proton intensity is constrained by Pb stability (moving long range encounters), and arc BPMs capabilities (still uncertain), • 5 1010 p/bunch is the maximum reachable in any case, • Number of bunches per beam is taken from “baseline scenario” for Pb-Pb run in 2015-2016, • Integrated luminosity assumes same integrated over peak luminosity ratio as in 2013. • ALICE will level at ~1028 and 1029 cm-2s-1 in Run 2

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